In many fields of activity having a scientific basis, scientific instruments are used to analyse, record, and monitor the outputs of various devices. Such devices include strain gauges, electro-cardiograph (ECG) devices, microphones, and pressure, temperature, flow rate and like transducers. Accordingly, such scientific instruments are used in civil engineering, electrical engineering, acoustics, hydraulic engineering, chemical processes, bio-medical engineering and so on.
A wide range of such scientific instruments are generally required in order to undertake desired measurements. Such instruments include generators for various wave-forms (such as sine, square, ramp, and triangle); signal processing devices such as differentiators, integrators, filters, multipliers, and so on; analysers such as that required to carry out the Fast Fourier Transform, and various recording devices such as a chart recorder, a data logger, a cathode ray oscilloscope or a transient recorder.
Such instruments or devices are each relatively expensive and thus any research institution, or like organisation only has a limited number of such devtces. Accordingly, there is considerable competition amongst persons or groups within such organisations who wish to utilise the devices. Once the devices have been obtained in order to carry out the intended operation, it is necessary for the devices to be located together, interconnected, and tested in order to ensure that the interconnections are correct. Only once this procedure has been carried out is it then possible to commence the intended operation.
It is known in the art to provide instruments which are essentially highly advanced cathode ray oscilloscopes. One such instrument is sold under the name SUPERSCOPE by G W Instruments of Summerville, Mass. U.S.A. 02143 and enables waveforms captured by what is essentially a storage oscilloscope to also be displayed on an APPLE (Registered Trade Mark) Macintosh (Registered Trade Mark) Computer. However, this device does not appear to emulate instruments, rather it only captures and stores for subsequent display the output of such instruments.
It is also known to utillse software for data acquisition. One such program offered by LABTECH of Willmington, Mass. and San Francisco, Calif., U.S.A. is a graphical interface which again accepts signals from various hardware items external to the computer. The software collects data from multiple channels, carries out an analysis and, if necessary a reduction of the data and produces displays. This activity is available in real-time. Again, no attempt is made to emulate the function of scientific instruments. A further difference is that the graphical interface connects to a number of different machines, rather than being essentlally integrated into one unit.
A data acquisition and analysis system sold under the trade name LABVIEW2 by National Instruments of Austin, Tex., U.S.A. is also known. In this system, icons are used to represent both data acquisition functions and data analysis functions. These icons are used to generate executable code which is only executed by the personal computer into which the software of the system is loaded. This system uses no hardware, only software. The data acquisition and analysis functions can be sequentially linked so that data input into the computer can be first acquired and then analysed. Finally the analysed data is presented. It is to be noted that the computer functions to make desired inter-connections between external instruments but does not emulate instruments or compile a program to replicate the signal processing functions of an array of inter-connected instruments. For example, no provision for feedback from one icon back to another in the control sense, is made. The slow processing speeds, and the indetermine nature of the multi-tasking environment of the APPLE (Registered Trade Mark) personal computer, require the provision of a time "co-ordinate" to accompany the acquired data.
This system is a virtual instrument which is to say it is characterised by software simulation only and is to be contrasted with the new concept of emulation. Emulation involves flexible, multipurpose, re-programmable hardware which executes code derived from a graphic compilier at a fast operating speed which enables real time instrument emulation.